This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The telencephalon is divided into many functionally distinct areas. These areas are characterized by different combinations of gene expression, cytoarchitecture, and pattern of connections. A major question in the field is how these areas are specified. Recent work has identified evolutionary conserved enhancer elements that regulate gene expression in sharply demarcated regions in the ventricular zone of the E11.5 mouse cortex. The spatial extent of these regions is regulated by multiple transcription factors. Our lab is interested in identifying these transcription factors using mass spectroscopy. Our approach involves applying nuclear lysate from specific forebrain regions to enhancer elements. The proteins that specifically bind the enhancer will be isolated and identified using mass spectroscopy.